1. Field of the Invention
This invention is related in general to the field of data storage systems. In particular, the invention consists of a system for managing computer support systems.
2. Description of the Prior Art
In FIG. 1, a computer storage system 10 includes host servers (“hosts”) 12, data processing servers 14, a data storage system 16, and various support systems 18 such as a power supply 18a, a battery 18b, a fan 18c, and a temperature sensor 18d. Each data processing server 14 may include a plurality of processing devices grouped into a processing cluster (“cluster”) 20 and may be substantially identical and redundant. Imposed upon the physical components of the computer storage system 10 may be a multitude of virtualized storage servers referred to as images 22 as shown in FIG. 2. Each image 22 typically resides on two or more clusters. In the event of a cluster failure, however, an image 22 can failover to the remaining clusters.
The support systems 18 are hardware devices that provide services other than data storage. Each image 22 typically has access to and can use these devices. Additionally, these support devices 18 may have the ability to generate reports related to events, faults, and failures. Images 22 communicate with support systems 18 through a remote procedure call (“RPC”) adapter 24.
In one configuration, each image 22 would access the support systems 18 through its own RPC adapter 24. However, this approach is extremely expensive due to the cost of redundant hardware. Additionally, each RPC adapter 24 may be dramatically underutilized. Therefore, it is desirable to have a system for establishing communicating with support systems 18 that is efficient and economical.
In U.S. Pat. No. 5,633,999, Clowes et al. disclose workstation-implemented data storage re-routing for server fault-tolerance. Cross-mirroring in a multi-host data storage system provides fault-tolerance without significant redundant hardware and without a single point of failure in the data storage paths. However, Clowes does not describe a system for sharing access to support systems through a set of RPC adapters.
Another approach is to utilize a static multi-tiered architecture that allows one image to own the RPC adapters 24 and require that other images access the support systems 18 indirectly through the owning image. However, a problem occurs if the image 22 tasked with managing the support systems 18 fails, precluding use of the support systems 18 by the other viable images. Accordingly, it is desirable to have a system for establishing ownership over support systems 18 while allowing direct access to the RPC adapters 24 by other images 22.
In a traditional dynamic system, an RPC adapter 24 may be owned by one image at a time, only for as long as the image requires use of the support systems 18. The RPC adapter 24 is then released and made available for use by another image. However, a contention may develop between images 22 seeking concurrent control over the RPC adapter 24. Accordingly, it is desirable to have a system for establishing control of the RPC adapter 24 that prevents contention.
In U.S. Pat. No. 5,553,287, Bailey et al. disclose a computer system for switchably connecting an input/output (“I/O”) device to a host via a channel subsystem in connection with means for dynamically managing I/O connectivity. Bailey's invention includes a centralized control lock associated with hardware resources. However, no resources are provided for identifying which image is responsible for managing each hardware resource. Accordingly, it is desirable to have a master lock that identifies the owning image.